The soil fabric varies significantly depending on the deposition process that forms the grain skeleton. Each deposition method produces a specific type of soil fabric, which can be linked to a particular soil density. When represented as relative density, determined using limit densities from standard index tests, a wide range of relative densities can be observed for different sands produced by the same deposition method. The influence of this variation in relative density, resulting from a single deposition method, on the development of the excess pore water pressure (PWP) should be further investigated. A fast testing of the excess PWP accumulation in sandy soils during undrained cyclic shearing can be easily performed using the newly developed PWP Tester. In the PWP Tester, specimens are prepared through sedimentation in water, which yields a comparable fabric in different sands but significantly different relative densities. Despite these relative density differences, the rate of the excess PWP evolution during undrained shearing is remarkably similar among different sands. This indicates that relative density should not be regarded as a primary factor influencing the development of the excess PWP and that the soil fabric plays equal or even a greater role.

The number of studies concerning the shear strength of resedimented alluvial soils is extremely limited compared to the studies conducted on fine-grained marine sediments, since alluvial soils are generally tested in remolded or reconstituted state especially in the studies investigating their liquefaction potential. In this study, estimation models were developed to predict cohesion (c) and internal friction angle (phi) parameters of a fine-grained alluvial soil using resedimented samples. A total of 60 undisturbed soil samples were obtained from Bafra district of Samsun province (Turkiye) by core drilling. A cone penetration test with pore water pressure measurement (CPTu) was also carried out alongside each borehole to determine the over-consolidation ratios of the samples. Physical-index property determinations and triaxial tests were conducted on the undisturbed samples. 20 sample sets were created with known physical, index, and strength characteristics. The samples are classified as CH, CL, MH, and ML according to the Unified Soil Classification System, with liquid and plastic limits ranging from 31.6-75% and 19.3 to 33.6% respectively. The c and phi values of the samples varied from 4.1 to 46.1 kPa and 26 to 35 degrees respectively. The samples were then resedimented in the laboratory under conditions reflecting their original in-situ properties, and triaxial tests were repeated. The c and phi values of the resedimented samples ranged from 5.3 to 24.5 kPa and 28 to 32 degrees respectively. The results indicate that the c values of the resedimented samples are generally lower than those of the undisturbed samples, whereas upper and lower bounds for phi values are similar. Multivariate regression analyses (MVR) were utilized to develop estimation models for predicting c and phi using strength and physical properties of 20 soil samples as independent variables. Three estimation models with R-2 values varying between 0.723 and 0.797 were proposed for c and phi which are statistically significant for p <= 0.05. Using artificial neural networks (ANN), the estimation models developed by MVR were replicated to validate the models. ANN yielded very similar results to the MVR, where the R-2 values for the correlations between c and phi values predicted by both methods varied from 0.852 to 0.955. The results indicate that c and phi values of undisturbed samples can be estimated with acceptable accuracy by determining basic physical and index properties of the disturbed samples and shear strength parameters of the resedimented samples. This approach, which enables the reuse of disturbed soil samples, can be used when undisturbed soil samples cannot be obtained from the field due to economic, logistical, or other reasons. Further research on the shear strength parameters of resedimented alluvial soils is needed to validate the estimation models developed in this study and enhance their applicability to a wider range of alluvial soils.

The Dead Sea Transform (DST), a prominent tectonic feature on Earth's crust, provides an exceptional natural laboratory for investigating the dynamic processes associated with continental rifting and its subsequent evolution. This study focuses on the sedimentary and tectonic evolution of the Yesha Fault, a marginal fault of the DST. Along the Yesha Fault, a distinct, elongated depression, known as the Yesha Valley was formed. Through detailed analysis of sedimentary sequences from boreholes and geochronological data obtained by optically stimulated luminescence and magnetostratigraphy, this research aims to refine the understanding of sedimentation patterns, rates, and tectonic activity associated with this marginal fault. The initial formation of the Yesha Valley, postdating the Brunhes-Matuyama reversal (-773 ka), was driven by normal faulting, resulting in an accommodation space progressively infilled with clastic and aeolian sediments. The sedimentary record reveals four distinct cycles of calcic soil between -780 ka and -450 ka, indicative of short episodes of tectonic subsidence, each followed by a period of tectonic quiescence, during which carbonate accumulated and calcic soils have developed. Following -450 ka, the sedimentary sequence accumulated in the subsiding valley lacks evidence of abrupt tectonic events, suggesting a transition to a tectonic regime dominated by gradual creep. During the last glacial period, sedimentation is characterized by clay deposition, with more hydric conditions and increased organic content observed between 4 and 6.5 m, whereas the uppermost 2 m of the soil reflects the influence of recent anthropogenic activity. Sediment accumulation rates within the Yesha Valley exhibit considerable variability, ranging from 20.8 cm/ka to 1.8 cm/ka, with an average of 3.2 cm/ka. These rates are an order of magnitude lower than those observed in the adjacent Hula Basin, indicating a slower tectonic regime along the marginal Yesha Fault and valley.

This work is dedicated to the study and investigation of thermoxidation processes in crude oil and petroleum products. The study of thermoxidation processes in crude oil and petroleum products was carried out using various analytical techniques, including IR, NMR, UV, small-batch reactor, TGA, DSC, DTA, thermochemical luminescence and others. One of the key characteristics of crude oil and petroleum products is their thermo-oxidative stability. During thermoxidation, hydrocarbons in the oil oxidize in an oxygen-rich environment, forming undesirable compounds such as hydroperoxides, alcohols, ketones, and others. These changes lead to increased viscosity and alterations in the chemical and physical properties of the product. The hydroperoxides formed during the process play a critical role as free radical initiators, which accelerate oxidation reactions. At higher temperatures, these reactions can produce solid particles, resins, and even sediments. In engines, such sediments can disrupt the normal flow within the fuel system, leading to improper process management, engine damage, increased operational costs, reduced efficiency, and environmental pollution. Effective management of oxidation processes and the implementation of preventive measures are crucial to addressing environmental issues such as soil and water contamination. In the oil industry, it is essential to enhance the understanding and control of oxidation processes to meet both the increasing global demand and the tightening environmental regulations. This approach not only improves production efficiency but also ensures the protection of the environment

Lake sediments record the environment during the lake sedimentation whose characteristics can infer environmental changes and human activities. In this study, the Pb-210 chronologies and sedimentation rate of the sediment core in Honghu Lake were calculated by the Constant Rate of Supply model. The characteristics of the sedimentary environment were analysed by using physical and chemical indicators. Four stages were divided as follows: Stage A (before 1900): The relatively low sedimentation rate and nutrient content indicated an extremely stable sedimentary environment. Stage B (1900-1949): With the growth of population, the intensity of land use began to increase, with an averaged sedimentation rate of 0.252 gcm(-2)a(-1). Stage C (1949-1980): The sedimentation rate and nutrient content increased markedly. The intense human activity has damaged the surrounding vegetation leading to soil erosion and accelerated sedimentation rate. With the deterioration of the lake water environment, the organic matter source was mainly the internal source represented by algae and bacteria. Stage D (1980-2011): Influenced by the difference in land use types along the coast, the sedimentation rate of HH-A (0.570 gcm(-2)a(-1)) is higher than that of HH-B (0.445 gcm(-2)a(-1)). The results are of significance to the management of rural lakes and reservoirs.

This study proposes a resolved framework coupling computational fluid dynamics (CFD) with discrete element method (DEM) to simulate the sedimentation of granular sand. Realistic sand particles were reconstructed by spherical harmonic representation combined with the multi-sphere clump method, and a fictitious domain method for irregular clumps was further developed to solve the fluid-particle interaction. This resolved CFD-DEM offers a direct and robust approach for computing real fluid forces on irregular-shaped granular sands, without relying on any empirical drag force models. Initially, the effectiveness and accuracy of the proposed CFD-DEM were validated through a series of single-particle free settling simulations for various ideal-shaped particles. Critical fluid-particle interacting behaviors in terms of drag force and wake structure were mainly investigated and corroborated with experimental data. The study subsequently progressed to simulate the sedimentation processes of various granular sand assemblies composed of realistic-shaped sand particles, utilizing the proposed CFD-DEM. Detailed numerical analyses concentrated on particle-scale mechanics during sedimentation, including settling trajectories and velocities of particles, as well as the coordination and anisotropy of inter-particle contacts. The results and findings gained from this study provide a novel insight into the micro-mechanisms underlying the sedimentation and accumulation process of granular soils in geological environments.

The Baiyun Canyon area on the Northern Slope of the South China Sea is a potential hotspot for oil and gas resource development, but the sediment characteristics and sedimentary environment in this region present challenges for offshore engineering. This study comprehensively analyzed the physical, and mechanical properties of sediments in the area using geophysical exploration, engineering geological investigation, fixed-point sampling and hydrological observation. The engineering geological characteristics and sedimentary environment of surface sediments in the Baiyun Canyon area were studied, and the relationship between physical and mechanical properties and sedimentary environment was explored. The study revealed that the sediments in this area consist mainly of organic soft clay with high water content, low density, high pore ratio, high liquid limit, high plasticity and low strength. The physical and mechanical properties of the sediments vary, with the mechanical properties exhibiting higher variability than the physical properties. The research findings offer a scientific basis for understanding the seabed soil properties for designing submarine engineering structures in the deep waters of the northern South China Sea. This study holds significant theoretical and practical implications for oil and gas exploration and offshore engineering construction.

Splays-fan-shaped depositional landforms produced by overbank deposition by unconfined flows-can damage structures, degrade arable land and incur substantial mitigation costs. Splay-related hazards along many rivers are likely to worsen with the increasing magnitude and frequency of major floods. The highly incomplete understanding of splays on braided streams is a conspicuous knowledge gap in a changing world with more frequent and intense floods. The largest recorded flood on the braided, sand-dominated lower Platte River (eastern Nebraska, USA) in March 2019 resulted from the rapid melting of a deep, moist snowpack during an extreme rain-on-snow, bomb-cyclone event. This flood produced 32 large (as much as 234 ha) splays that buried structures and cropland under sand. A total of 1,438 ha of row crop was buried, equating to 1.2 million dollars in lost revenue. These splays diverged from the channel by 14 degrees to 104 degrees along a 122 km reach. The topography of preexisting abandoned channels strongly controlled the shape and orientation of most splays, although forested areas tended to trap or divert sediment. The flood eroded 2.2 to 202 m(2) m(-1) of the streambank at 11 of the splays. The five largest splays (>100 ha) deposited as much as 2.4 m of sand. Ground-penetrating radar profiles of the largest splay indicate that it consisted almost entirely of overbank deposits exhibiting simple downstream accretion that buried the pre-flood soil under <= 1 m or less of sand. Locally, however, this soil was eroded during the flood. Climate models predict increasing winter precipitation in the Platte River basin; therefore, the frequency of major floods should increase, making splays recurrent hazards. Our geomorphic assessment of the splays on the lower Platte River illustrates the need for future hazard and mitigation planning.

Sediment deposition significantly impacts soil erosion processes, consequently influencing the geographical morphology and surrounding environments of reservoirs and estuaries. Given the intricate nature of sediment deposition, it is imperative to consolidate and analyze existing research findings. Presently, studies on sediment settling velocity primarily employ theoretical, laboratory, and field experimentation methods. Theoretical approaches, rooted in mechanics, examine the various forces acting on sediment particles in water to derive settling velocity equations. However, they often overlook external factors like temperature, salinity, organic matter, and pH. Although laboratory experiments scrutinize the influence of these external factors on sedimentation velocity, sediment settling is not solely influenced by individual factors but rather by their collective interplay. Field observations offer the most accurate depiction of sediment deposition rates. However, the equipment used in such experiments may disrupt the natural sedimentation process and damage flocs. Moreover, measurements of sediment particle size from different instruments yield varied results. Additionally, this paper synthesizes the impact of suspended sediment concentration, particle size, shape, temperature, salinity, and organic matter on sediment settling velocity. Future research should focus on innovating new laboratory observation methods for sediment settling velocity and utilizing advanced scientific and technological tools for on-site measurements to provide valuable insights for further investigation into sediment settling velocity.

Check dams and afforestation are widely used to control debris flows; however, the combined effects of mitigation changes caused by sedimentation behind the check dams as well as the growth of vegetation are unclear. This paper reports long-term measurements of the erosion base level behind check dams along the Shengou gully, which is an active debris flow gully with 19 shallow soil landslides along its banks. The loose sediment on the shallow soil landslides, which is affected by afforestation, is the main source of material and energy for debris flows in this gully. The change in the mechanical properties of the loose sediment on the shallow soil landslides was determined. Based on the mechanical properties of the shallow soil landslides and the erosion base level behind the check dams, the volume and potential energy of the shallow soil landslide sediment were calculated. A model of the vegetation coverage, shallow soil landslide energy, and debris flow volume was established and applied to the Shengou gully. The results show that the model can evaluate the different benefits of check dams and afforestation on debris flow mitigation given the sedimentation behind the check dams and the vegetation growth.